Computer Code: |
TSI |
Preferred Map Code: |
TSI |
Status Code: |
Pending Upgrade |
Age range: |
Soudleyan Substage (OY)
— Soudleyan Substage (OY) |
Lithological Description: |
Grey, thinly laminated to pervasively bioturbated siltstones and interbedded mudstones, with local massive, lenticular sandstones and channelised intraformational mudstone conglomerates and a localised tuff member, the Pen Bwlch Tuff. |
Definition of Lower Boundary: |
Conformably overlies rocks of the Swch Gorge Tuff Formation (qv). |
Definition of Upper Boundary: |
Conformably overlain by rocks of the Pandy Tuff Formation (qv). |
Thickness: |
210 to 250m |
Geographical Limits: |
Not defined. |
Parent Unit: |
Not Available (!)
|
Previous Name(s): |
Teirw Beds [Obsolete Name And Code: Use TSI]
(TWB)
|
Alternative Name(s): |
none recorded or not applicable
|
Stratotypes: |
none recorded or not applicable |
Reference(s): |
Brenchley, P J. 1978. The Caradocian rocks of the North and West Berwyn Hills. Geological Journal, Vol. 13, 137-164. |
1:50K maps on which the lithostratigraphical unit is found, and map code used: |
E120
E137
|